大鼠脊髓损伤后不同时间点5-HT2A受体免疫反应性的变化

Changes of serotonin 2a receptor cord transection immunoreactivity after rat spinal at different time

目的：研究大鼠脊髓骶段（第2骶节）横断伤后5-羟色胺2A受体免疫反应（5-HT2AR-IR）的变化。方法：大鼠随机分为7组，即2h、8h和1d、2d、7d、30d、60d组，每组又随机分为手术组和假手术组。手术组在大鼠第2骶髓节段完全横断，假手术组只去除椎板，保留硬脊膜的完整，采用免疫荧光组织化学方法检测脊髓损伤下段5-HT2A-IR的变化。结果：2、8h手术组脊髓前角运动神经元区5-HT2A-IR密度与假手术组比较无明显不同，1d后与假手术组比较开始增高，5-HT2A-IR密度随时间延长呈逐渐增加的趋势，直到手术后60d达到最高水平。结论：慢性脊髓骶段完全横断后脊髓前角运动神经元的5-HT2A受体上调可能是5-羟色胺去神经支配后超敏感反应和痉挛发生的潜在机制。

Objective： To explore the changes of serotonin 2a （5-HT2A） receptor immunoreacitivity following chronic spinal transection at S2. Methods： Wistar rats were randomly divided into 7 groups： 2h, 8h, ld, 2d, 7d, 30d and 60d groups. And, animals in each group were subdivided into sham and operated groups. In operated group, the spinal cord was transected completely at $2, while the only the second lumbar vertebral lamina was removed but the dura was kept intact in sham animals. Then, expression of 5-HT2A receptor below the lesion of the spinal cord was detected immunohistochemically. Resuits：Compared with those in sham animals, the immunoreactivity of 5-HT2A receptor in model animals were comparable to sham at postoperative hour 2 and 8, and increased gradually and peaked at postoperative day 60. Conclusion： The upregulation of 5-HT2A receptor may underlay the supersensitivity of spinal motor neurons by 5-HT denervation and spasticity after a complete chronic transection of the spinal cord.